1. Field of the Invention
The present invention relates to a sheet resin composition for back-grinding or underfilling of a silicon wafer, a process for manufacturing a semiconductor device, and a semiconductor device.
2. Discussion of the Related Art
With the recent increasing trends for high-density semiconductor devices, a package system employing integrated circuit (IC) comprising bumps, which is so-called “flip chip,” has been rapidly widely used. In addition, owing to the requirement of manufacturing a thinner semiconductor device, in order to make a semiconductor wafer thinner, the wafer is subjected to so-called “back-grinding,” wherein the back side of the wafer is ground. Particularly, in these several years, with the spread of a semiconductor device so-called “chip scale package (CSP),” a technique of making a wafer comprising bumps even thinner has been demanded in the market. When such a thin wafer comprising bumps is obtained, there has been employed a process comprising subjecting a wafer to back-grinding to a desired thickness, and thereafter attaching bumps. However, a thin wafer obtained after back-grinding is difficult to transport. Moreover, from the aspect of the recent progressing trend for enlarging a diameter of a wafer, there has been strongly demanded in the market the development of a technique for carrying out a back-grinding process after attaching bumps.
As a means for solving the above problems, there has been known a process in which an adhesive tape for back-grinding is adhered to the active surface (the opposite surface of the surface subjected to back-grinding) of a wafer on which bumps exist, and then the wafer is subjected to back-grinding. However, it is difficult to sufficiently fill the ruggedness of the wafer surface due to the bumps with the adhesive tape for back-grinding. Therefore, there arise problems that water penetrates to the active surface of the wafer during back-grinding, that the ruggedness caused by the bumps on the ground surface of the wafer remains after back-grinding, and the like. Therefore, wafers cannot be efficiently obtained, and the resulting wafer does not sufficiently meet the requirement of the market. Further, the adhesive tape for back-grinding must be completely removed from the wafer surface after back-grinding.
On the other hand, when a chip with bumps obtained by cutting the wafer subjected to back-grinding by means of dicing is attached on a substrate, a liquid thermosetting resin so-called “underfilling material” is filled between the chip and the substrate, and the thermosetting resin is cured (underfilling step). The underfilling step is an indispensable technique for securing the reliability for electric connection between the chips and the substrate. However, the number of its treatment steps is large, wherein the process comprises the steps of applying flux on a substrate; attaching a chip on the substrate; cleaning out the flux; filling an underfilling material between the chip and the substrate; and curing the underfilling material. Therefore, an even simpler process has been demanded in the market.